Desighn of a Novel Compact Microstrip Uwb Band-pass Filter with 5.5 Ghz Band Rejection Function

In this paper, a new Ultra-Wideband (UWB) Band-Pass Filter (BPF) for UWB applications is presented. The proposed filter is based on ring resonator with inter-digital coupling at both sides. The inter-digital coupling is used to providing strong coupling and to introduce capacitance effect to achieve at pass-band response. To achieve band rejection characteristics L-shaped open stubs are incorporated in filter structure. The proposed filter is printed on a dielectric substrate of FR4 with relative permittivity (εr) of 4.4 and thickness of 1.6 mm. This filter operates from 2.95 GHz to upper 8.7 GHz for voltage standing wave ratio less than 2, except a frequency notched band of 5-5.9 GHz. Moreover, the achieved results show that proposed filter has a linear phase variation and a flat group delay with variation less than 0.2ns within the pass-bands, which is made this BPF filter suitable for ultra-wideband wireless communication.